Although there may be a need for privacy when taking or making phone calls, if your partner retreats to the other room every time the phone rings, there may be something more going on — especially if this behavior is new or has suddenly become more frequent. —Michael Howard

2. He deletes the text history on his phone.

Most people don't bother deleting old text messages (at least not until the phone is full). If your partner makes sure that old messages are deleted — or worse, he deletes them as soon as he finishes a conversation with someone — there may be more going on than just texting. —Michael Howard

3. He maintains multiple e-mail or social media accounts.

If you discover additional or hidden e-mail or social media sites, things are almost certainly not good. Simply put, people in committed relationships have no need to maintain accounts that their partners don't know about. If you discover one of these, it is time to be concerned. —Michael Howard

Infidelity, whether physical or emotional, will always result in lost time with friends and family. If your partner avoids social gatherings or activities, leaves early or arrives late because of some project or task, there may be a strong chance that he is spending time with someone else, whether on the phone, the computer, or in person. —Michael Howard

5. He suddenly spends tons of time with another person.

If your partner is suddenly spending a lot of time with a colleague, co-worker, friend, or even an acquaintance (particularly if that person is of the opposite sex), you may want to learn more about this relationship and the possibility that there may be an affair going on. —Michael Howard

6. He gives gifts or frequently volunteers to help another person.

Although it is nice to give gifts and do kind things for friends, family members, and even strangers, if your partner frequently gives gifts (especially those that are costly, take time and effort to prepare or have significant meaning) or volunteers to help out with projects around someone else's home, this may be a sign that he is having an emotional affair. —Michael Howard

Whether it's another woman's perfume or possibly a different brand of soap from showering elsewhere, your senses don't lie. If he's coming home freshly showered after a full day of work, it's a hint that he's having an affair. —Wendy Kay

8. He doesn't touch you as much.

Sometimes affection drops off a bit due to poor communication, unresolved issues or a recent argument. If this is unexplained behavior or he is repelling you with odd excuses, you may have a hint. At minimum, you have an issue in your relationship that needs to be addressed honestly. —Wendy Kay

9. He dresses differently.

Has your husband started to dress a little differently or does he keep his vehicle a bit cleaner? Has he been acting slightly happier and more cooperative, yet all of a sudden he is busier and leaving the house more often? If so, take heed. Take interest in his new activity/involvement if you're curious about what's really going on. —Wendy Kay

Does your man usually take the dog out for a half hour run every day, but now it's a 60-90 minute walk-run? Who is he running into all of a sudden at the dog park or in the neighborhood? If it's not "chatty Kathy," you may have a hint. Go along once in a while. —Wendy Kay

11. He picks fights.

Is your husband starting arguments that end up in him leaving the house a lot? Are his garments coming up missing here and there? If so, something is going on! —Wendy Kay

12. He's being extra secretive.

When your husband suddenly has a change in his "privacy" attitude — all of a sudden you're not supposed to know his whereabouts or who he's talking to on the phone and it's not close to your birthday, anniversary or upcoming gift-giving holiday — I think you know. —Wendy Kay

This may be shown as your partner is unengaged or overly engaged. We all, of course, go through emotional changes. However, you may notice that your partner's attitude has changed toward you over time. They may have become more self-absorbed and less interested in you or the relationship. Often, your partner may reject your offers of affection. Your best approach here is to pay attention and be curious. —Donn Peters

14. He's extremely angry.

Anger and criticism that borders on cruelty are hard to take for all of us. Your partner may treat you with rudeness or impatience. He may be more controlling and more critical than usual. You may sense an increase in the degree of unhappiness in your spouse that is difficult to understand. With some partners, you may actually see an increase in happiness as a result of being involved in an affair. —Donn Peters

15. You notice an increase in his work or his time spent away from home.

Work can be demanding. During these times of economic stress, most workplaces are demanding more and more from their employees. Workplace relationships can develop into romantic relationships simply because the amount of time spent together on a common task tends to bond people together. If your partner has trouble with boundaries, this could lead to a problem for your relationship. —Donn Peters

This would be especially telling if up until now, your partner has not shown much attention to his appearance. If your partner is having an affair, he has found a new source of love and affection. Looking good for his paramour is very important. —Donn Peters

17. He's overly defensive.

Defensiveness exists for many reasons. In the past, were you able to discuss issues openly and calmly? What you are looking for here is an increase in the normal amount of defensiveness. —Donn Peters

18. His appearance has changed.

Your partner, who previously dressed conservatively, is now suddenly buying designer boxer shorts and more trendy clothes. Or your partner, who never spent much time grooming himself, is now fussy about how his hair looks and uses grooming products he's never used before. —Susanne Jorgensen

Your partner, who usually avoided office parties and events, is now constantly attending them "for the sake of his career." Or your partner suddenly takes up and becomes obsessed with a new hobby or sport that keeps him away from home. Or your partner who usually is home for dinner every night now "works late" and takes more frequent "business trips." —Susanne Jorgensen

20. His attitude has changed.

Your laidback partner seems to have been injected with unusual enthusiasm, seems more happy, alive, energetic and is more kind and loving towards you, too. He may buy you more gifts and shower you with surprises, which (until now) has not been his natural character. —Susanne Jorgensen

21. He wants less "we time" and more "me time."

When you got together as a couple, you consciously or unconsciously negotiated how much "me time" you would have and how much "we time" you as a couple would have. Now, you are noticing a shift from "we" to your partner wanting much more "me" time. You aren't included to the degree you used to be in your partner's extra-curricular activities. —Susanne Jorgensen